• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
csisy

OpenGL
CSM (based on nvidia's paper) swimming

10 posts in this topic

Hi there

I know, there are some similar topics, but I don't understand the solution. I made the CSM based on this paper: [url="http://developer.download.nvidia.com/SDK/10.5/opengl/src/cascaded_shadow_maps/doc/cascaded_shadow_maps.pdf"]http://developer.download.nvidia.com/SDK/10.5/opengl/src/cascaded_shadow_maps/doc/cascaded_shadow_maps.pdf[/url]
with some "improvements". Here is the code:

I have a matrix which is used when I create the shadows
[CODE]
float texOffset = 0.5f + (0.5f / (float)shadowSize);
float bias = 0.003f;
textureMat = Matrix(0.5f, 0.0f, 0.0f, 0.0f,
0.0f, -0.5f, 0.0f, 0.0f,
0.0f, 0.0f, 1.0f, 0.0f,
texOffset, texOffset, -bias, 1.0f);
[/CODE]
Now, here is the frustum corner's computing:
[CODE]
void Shadow::ComputeFrustumCorners()
{
float& camAspect = scene->camera->aspect;
Vector3& camEye = scene->camera->eyePosition;
Vector3 dir;
dir.x = scene->camera->GetView().m[0][2];
dir.y = scene->camera->GetView().m[1][2];
dir.z = scene->camera->GetView().m[2][2];
Vector3 x;
x.x = scene->camera->GetView().m[0][0];
x.y = scene->camera->GetView().m[1][0];
x.z = scene->camera->GetView().m[2][0];
Vector3 y;
y.x = scene->camera->GetView().m[0][1];
y.y = scene->camera->GetView().m[1][1];
y.z = scene->camera->GetView().m[2][1];
tanHalfFov = tanf(scene->camera->fov * 0.5f);
float nPlaneH = tanHalfFov * nearPlane;
float nPlaneW = nPlaneH * camAspect;
float fPlaneH = tanHalfFov * farPlane;
float fPlaneW = fPlaneH * camAspect;
Vector3 nPlaneX = x * nPlaneW;
Vector3 nPlaneY = y * nPlaneH;
Vector3 fPlaneX = x * fPlaneW;
Vector3 fPlaneY = y * fPlaneH;
nPlaneCenter = camEye + dir * nearPlane;
fPlaneCenter = camEye + dir * farPlane;
frustumCorners[0] = nPlaneCenter - nPlaneX - nPlaneY;
frustumCorners[1] = nPlaneCenter - nPlaneX + nPlaneY;
frustumCorners[2] = nPlaneCenter + nPlaneX + nPlaneY;
frustumCorners[3] = nPlaneCenter + nPlaneX - nPlaneY;
frustumCorners[4] = fPlaneCenter - fPlaneX - fPlaneY;
frustumCorners[5] = fPlaneCenter - fPlaneX + fPlaneY;
frustumCorners[6] = fPlaneCenter + fPlaneX + fPlaneY;
frustumCorners[7] = fPlaneCenter + fPlaneX - fPlaneY;
}
[/CODE]
I get the x,y,z axes from the view matrix, so I don't have to compute these values.

And of course the "main part" of CSM; compute the viewproj matrix for the shadow map generation, and the "final matrix" for the "final" shadow rendering. I think I should modify this part to kill the swimming edges.
[CODE]
void Shadow::ComputeMatrices()
{
ComputeFrustumCorners();
view = Matrix::LookAt(Vector3::Zero, light->direction, Vector3::Up);
Vector3 min = Vector3::Max;
Vector3 max = Vector3::Min;
Vector4 transformed;
for (int i = 0; i < NUM_CORNERS; i++)
{
transformed = Vector4::Transform(frustumCorners[i], view);
transformed /= transformed.w;
if (transformed.x < min.x)
min.x = transformed.x;
if (transformed.y < min.y)
min.y = transformed.y;
if (transformed.z < min.z)
min.z = transformed.z;
if (transformed.x > max.x)
max.x = transformed.x;
if (transformed.y > max.y)
max.y = transformed.y;
if (transformed.z > max.z)
max.z = transformed.z;
}
float scaleX = 2.0f / (max.x - min.x);
float scaleY = 2.0f / (max.y - min.y);
float offsetX = -0.5f * (min.x + max.x) * scaleX;
float offsetY = -0.5f * (min.y + max.y) * scaleY;
cropMat.m[0][0] = scaleX;
cropMat.m[1][1] = scaleY;
cropMat.m[2][2] = 1.0f;
cropMat.m[3][0] = offsetX;
cropMat.m[3][1] = offsetY;
cropMat.m[3][3] = 1.0f;
// INFO: bias
float bias = 10.0f;
min.z -= bias;
max.z += bias;
proj = Matrix::OrthographicOffCenter(-1, 1, -1, 1, min.z, max.z);
viewProj = view * proj * cropMat;
finalMat = viewProj * textureMat;
}
[/CODE]

So the problem is that, when I move or rotate the camera (not the light), the shadow edges are swimming / flickering. What is the solution for my code?

Thanks for all replies!
0

Share this post


Link to post
Share on other sites
There's an article in ShaderX6 about stabilizing your cascades so that edges don't crawl as the camera moves, so if you have access to that you should give it a read. Otherwise I explained it in more detail in [url="http://www.gamedev.net/topic/591684-xna-40---shimmering-shadow-maps/"]this thread[/url].

The other option is to get your shadow filtering and resolution good enough so that you don't notice crawling edges, but doing this requires a combination of good shadow filtering techniques as well dynamic optimization of your cascade partitions based on what's visible to the camera.
2

Share this post


Link to post
Share on other sites
Thanks for the reply!

I put your code between the viewProj and the finalMat compute:

[CODE]
proj = Matrix::OrthographicOffCenter(-1, 1, -1, 1, min.z, max.z);
viewProj = view * proj * cropMat;
Vector3 shadowOrigin = Vector3::Transform(Vector3::Zero, viewProj);
shadowOrigin *= shadowHalfSize;
Vector2 roundedOrigin = Vector2(Helpers::MathHelper::Round(shadowOrigin.x), Helpers::MathHelper::Round(shadowOrigin.y));
Vector2 rounding = roundedOrigin - Vector2(shadowOrigin.x, shadowOrigin.y);
rounding /= ((float)shadowSize * 0.5f);
Matrix roundMatrix = Matrix::Translate(rounding.x, rounding.y, 0.0f);
viewProj *= roundMatrix;
finalMat = viewProj * textureMat;
[/CODE]

I think it works, because the static meshes' shadow is not flickering (I think [img]http://public.gamedev.net//public/style_emoticons/default/biggrin.png[/img]), but the character (the player) moves together with the camera, and its shadow is still flickering.

This can be solved by the bounding sphere instead of light AABB?

EDIT:
I read your post, and I understand that we need a fix size for the projection (this kills the flickering when rotating the camera) and a little round to texels (which kills the flickering when the camera moves). So I rewrite my code based on your code and the idea:
[CODE]
ComputeFrustumCorners();

// spheres for each split

Vector3 sphereCenter;
for (int i = 0; i < NUM_CORNERS; i++)
{
sphereCenter += frustumCorners[i];
}
sphereCenter /= NUM_CORNERS;

float sphereRadius = Vector3::Distance(sphereCenter, frustumCorners[0]);

float nearClip = 1.0f;
float backupDist = 10.0f + sphereRadius + nearClip;

Vector3 camPos = sphereCenter - light->direction * backupDist;
view = Matrix::LookAt(camPos, sphereCenter, Vector3::Up);

float bounds = sphereRadius * 2.0f;
float farClip = backupDist + sphereRadius;
proj = Matrix::Orthographic(bounds, bounds, nearClip, farClip);
viewProj = view * proj;

// round to texel

origin = Vector3::Transform(Vector3::Zero, viewProj);
origin *= shadowHalfSize;

originRounded.x = Helpers::MathHelper::Round(origin.x);
originRounded.y = Helpers::MathHelper::Round(origin.y);

rounding.x = originRounded.x - origin.x;
rounding.y = originRounded.y - origin.y;
rounding /= shadowHalfSize;

roundingMatrix = Matrix::Translate(rounding.x, rounding.y, 0.0f);
viewProj *= roundingMatrix;

// compute final components

finalMat = viewProj * textureMat;
viewFrustum->Update(viewProj);
[/CODE]

Is this code correct? If it is, there are some problem: my character (which moves with the camera) still flickering and the "backupDist" is really game and eyeposition relevant, so I can't hardcode it.

Or am I doing something wrong?
0

Share this post


Link to post
Share on other sites
If geometry moves in world space then it is still going to flicker, you can't fix that by stabilizing cascades.

As for the backup distance, it's true that it's very annoying but you'd have the same problem in your original implementation, which is that objects behind the projection's near clip plane will get clipped out and so you have to have some means of "pulling back" the minz value. In D3D10/D3D11 there is actually a really nice solution to this problem, which is that you can turn of Z clipping and then objects behind the near clip plane won't get clipped. However as far as I know there is no equivalent for D3D9, so you're kind of stuck. The best you can do is try to automatically determine the required min z distance based on the extents of your level geometry.
2

Share this post


Link to post
Share on other sites
Thanks for your reply!

So isn't there any solution for the moving objects? And I have to compute dinamically the min and max values depended on the scene. I'll use a space-partitioning, maybe I will be able to use it to determine the min and max values.

Now, my static objects aren't flickering, and your solution is faster than my (nvidia's) old one, so it is awesome! :) Thanks for your help!
0

Share this post


Link to post
Share on other sites
Hm, it's strange. Yesterday, I didn't noticed this bug (see the pictures). I use this code now:

[CODE]
sphereCenter = Vector3::Zero;
for (int i = 0; i < NUM_CORNERS; i++)
{
sphereCenter += frustumCorners[i];
}
sphereCenter /= NUM_CORNERS;

sphereRadius = Vector3::Distance(sphereCenter, frustumCorners[0]);
sphereBounds = sphereRadius * 2.0f;

float nearClip = 1.0f;
float backupDist = 20.0f + nearClip + sphereRadius;
float farClip = backupDist + sphereRadius;

camPosition = sphereCenter - light->direction * backupDist;
view = Matrix::LookAt(camPosition, sphereCenter, Vector3::Up);

proj = Matrix::Orthographic(sphereBounds, sphereBounds, nearClip, farClip);
viewProj = view * proj;
[/CODE]

[attachment=9724:s1.JPG]
[attachment=9723:s2.JPG]

EDIT:
I compiled a Release from the code, here is the binaries, if someone would like to try it.
[attachment=9725:ShadowTest.zip]
0

Share this post


Link to post
Share on other sites
It occurred to me that if you can't turn of z clipping, then you might be able to just clamp your vertex position to the near plane in the vertex shader by setting the projected z coordinate to max(z, 0.0f). I'm not sure if it would cause problems since I haven't tried it or heavily thought it through, but I think it might work. Then you could just size the orthographic projection to the min and max of the frustum.
0

Share this post


Link to post
Share on other sites
I render the shadowmap to the screen, and it looks like the sphereBounds was too "small". And I find the problem, I was stupid [img]http://public.gamedev.net//public/style_emoticons/default/smile.png[/img]
When I computed the sphere's center, I get the radius from the d(center, corners[0]), which is the near-left-bottom corner of the frustum. The correct is the d(corners[0], corners[6]), where the 6th corner is the far-right-top corner.

[CODE]
sphereBounds = Vector3::Distance(frustumCorners[0], frustumCorners[6]);
sphereRadius = sphereBounds * 0.5f;
[/CODE]

Now, it works really good. Thanks for your help, the topic is solved (for me).

Ps.:
Can I set the topic to solved state, or set your post as a solution?

EDIT:
I have to use another little hardcoded thing:
[CODE]
sphereBounds = Vector3::Distance(frustumCorners[0], frustumCorners[6]) + 5.0f;
[/CODE]
because the camera sees the scene from top, and the sphereBounds wasn't big enough. Edited by csisy
0

Share this post


Link to post
Share on other sites
Hi again!

I've tested the shadows with a different camera view and I noticed that the shadowmap is maybe wrong. I uploaded a video yesterday which shows the problem:
[url="http://www.youtube.com/watch?v=HWmWCb2HdCA"]http://www.youtube.com/watch?v=HWmWCb2HdCA[/url]

When I turn the camera right the Sun should "looks" right too, but now the Sun "looks" left. And visa versa.

Here is the important code. Can anyone check it?

[CODE]
Shadow::Shadow(Base::Game* _game, Game::Scene* _scene)
: Renderer(_game, _scene)
{
vsShadowMap = 0;
vsShadowMapAnim = 0;
vsCombine = 0;

psShadowMap = 0;
psCombine = 0;

rtShadowMap = 0;
depthStencil = 0;
depthStencilOld = 0;

frustumCorners = 0;
viewFrustum = new ViewFrustum();

shadowSize = game->GetConfig()->GetShadowSize();
bias = 0.001f;

sphereBonus = 5.0f;
backupBonus = 20.0f;
}
[/CODE]
[CODE]
void Shadow::ComputeFrustumCorners()
{
float& camAspect = scene->camera->aspect;
Vector3& camEye = scene->camera->eyePosition;

Vector3 dir;
dir.x = scene->camera->GetView().m[0][2];
dir.y = scene->camera->GetView().m[1][2];
dir.z = scene->camera->GetView().m[2][2];

Vector3 x;
x.x = scene->camera->GetView().m[0][0];
x.y = scene->camera->GetView().m[1][0];
x.z = scene->camera->GetView().m[2][0];

Vector3 y;
y.x = scene->camera->GetView().m[0][1];
y.y = scene->camera->GetView().m[1][1];
y.z = scene->camera->GetView().m[2][1];

tanHalfFov = tanf(scene->camera->fov * 0.5f);

float nPlaneH = tanHalfFov * nearPlane;
float nPlaneW = nPlaneH * camAspect;
float fPlaneH = tanHalfFov * farPlane;
float fPlaneW = fPlaneH * camAspect;

Vector3 nPlaneX = x * nPlaneW;
Vector3 nPlaneY = y * nPlaneH;
Vector3 fPlaneX = x * fPlaneW;
Vector3 fPlaneY = y * fPlaneH;

nPlaneCenter = camEye + dir * nearPlane;
fPlaneCenter = camEye + dir * farPlane;

frustumCorners[0] = nPlaneCenter - nPlaneX - nPlaneY;
frustumCorners[1] = nPlaneCenter - nPlaneX + nPlaneY;
frustumCorners[2] = nPlaneCenter + nPlaneX + nPlaneY;
frustumCorners[3] = nPlaneCenter + nPlaneX - nPlaneY;

frustumCorners[4] = fPlaneCenter - fPlaneX - fPlaneY;
frustumCorners[5] = fPlaneCenter - fPlaneX + fPlaneY;
frustumCorners[6] = fPlaneCenter + fPlaneX + fPlaneY;
frustumCorners[7] = fPlaneCenter + fPlaneX - fPlaneY;
}
void Shadow::ComputeMatrices()
{
ComputeFrustumCorners();

// search corners' center
sphereCenter = Vector3::Zero;
for (int i = 0; i < NUM_CORNERS; i++)
{
sphereCenter += frustumCorners[i];
}
sphereCenter /= NUM_CORNERS;

// get sphere radius
sphereBounds = Vector3::Distance(frustumCorners[0], frustumCorners[6]) + sphereBonus;
sphereRadius = sphereBounds * 0.5f;

// near, far and cameraPosition
float nearClip = 1.0f;
float backupDist = nearClip + sphereRadius + backupBonus;
float farClip = backupDist + sphereRadius + sphereBonus;

camPosition = sphereCenter - light->direction * backupDist;
view = Matrix::CreateLookAt(camPosition, sphereCenter, Vector3::Up);

proj = Matrix::CreateOrthographic(sphereBounds, sphereBounds, nearClip, farClip);
viewProj = view * proj;

// round to texel

origin = Vector3::Transform(Vector3::Zero, viewProj);
origin *= shadowHalfSize;

originRounded.x = Helpers::MathHelper::Round(origin.x);
originRounded.y = Helpers::MathHelper::Round(origin.y);

rounding.x = originRounded.x - origin.x;
rounding.y = originRounded.y - origin.y;
rounding /= shadowHalfSize;

roundingMatrix = Matrix::CreateTranslate(rounding.x, rounding.y, 0.0f);
viewProj = viewProj * roundingMatrix;

// compute final components

finalMat = viewProj * textureMat;
viewFrustum->Update(viewProj);
}
[/CODE]

I would be grateful if anyone could help me. Edited by csisy
0

Share this post


Link to post
Share on other sites
Stabilizing the shadowmap requires a few steps:
[list]
[*]Padding up the shadowmap by 1 additional texel than required, then translating the shadowmap projection by an offset so that the center texel is centered at all times. This will stop the crawling when you translate the camera.
[*]Mapping the visible part of the view frustum to a sphere before projected that into a texture, will protect it from crawls caused by rotating the camera.
[*]If your camera's field of view animates, the shadows will also crawl as the view frustum will dynamically make the fit sphere larger or smaller. This can be hidden by making taking the FOV and rounding it up into buckets of increments that affect the sphere fitting, or you can just live with it if you don't change the FOV more or at all. The bucket strategy will avoid the crawl but you will get pops when changing buckets instead. If you constrain the min and max FOV well enough you could probably use a single value and never see a pop.
[/list]
1

Share this post


Link to post
Share on other sites
I don't change the FOV. :) The only shadow flickering comes on when I move an object (the character with the camera). When I disabled the rounding the result was better for moving objects, but for static objects (of course) the flickering comes back. So for moving objects the rounding is the "bad step".
0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0

  • Similar Content

    • By Solid_Spy
      Hello, I have been working on SH Irradiance map rendering, and I have been using a GLSL pixel shader to render SH irradiance to 2D irradiance maps for my static objects. I already have it working with 9 3D textures so far for the first 9 SH functions.
      In my GLSL shader, I have to send in 9 SH Coefficient 3D Texures that use RGBA8 as a pixel format. RGB being used for the coefficients for red, green, and blue, and the A for checking if the voxel is in use (for the 3D texture solidification shader to prevent bleeding).
      My problem is, I want to knock this number of textures down to something like 4 or 5. Getting even lower would be a godsend. This is because I eventually plan on adding more SH Coefficient 3D Textures for other parts of the game map (such as inside rooms, as opposed to the outside), to circumvent irradiance probe bleeding between rooms separated by walls. I don't want to reach the 32 texture limit too soon. Also, I figure that it would be a LOT faster.
      Is there a way I could, say, store 2 sets of SH Coefficients for 2 SH functions inside a texture with RGBA16 pixels? If so, how would I extract them from inside GLSL? Let me know if you have any suggestions ^^.
    • By KarimIO
      EDIT: I thought this was restricted to Attribute-Created GL contexts, but it isn't, so I rewrote the post.
      Hey guys, whenever I call SwapBuffers(hDC), I get a crash, and I get a "Too many posts were made to a semaphore." from Windows as I call SwapBuffers. What could be the cause of this?
      Update: No crash occurs if I don't draw, just clear and swap.
      static PIXELFORMATDESCRIPTOR pfd = // pfd Tells Windows How We Want Things To Be { sizeof(PIXELFORMATDESCRIPTOR), // Size Of This Pixel Format Descriptor 1, // Version Number PFD_DRAW_TO_WINDOW | // Format Must Support Window PFD_SUPPORT_OPENGL | // Format Must Support OpenGL PFD_DOUBLEBUFFER, // Must Support Double Buffering PFD_TYPE_RGBA, // Request An RGBA Format 32, // Select Our Color Depth 0, 0, 0, 0, 0, 0, // Color Bits Ignored 0, // No Alpha Buffer 0, // Shift Bit Ignored 0, // No Accumulation Buffer 0, 0, 0, 0, // Accumulation Bits Ignored 24, // 24Bit Z-Buffer (Depth Buffer) 0, // No Stencil Buffer 0, // No Auxiliary Buffer PFD_MAIN_PLANE, // Main Drawing Layer 0, // Reserved 0, 0, 0 // Layer Masks Ignored }; if (!(hDC = GetDC(windowHandle))) return false; unsigned int PixelFormat; if (!(PixelFormat = ChoosePixelFormat(hDC, &pfd))) return false; if (!SetPixelFormat(hDC, PixelFormat, &pfd)) return false; hRC = wglCreateContext(hDC); if (!hRC) { std::cout << "wglCreateContext Failed!\n"; return false; } if (wglMakeCurrent(hDC, hRC) == NULL) { std::cout << "Make Context Current Second Failed!\n"; return false; } ... // OGL Buffer Initialization glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT); glBindVertexArray(vao); glUseProgram(myprogram); glDrawElements(GL_TRIANGLES, indexCount, GL_UNSIGNED_SHORT, (void *)indexStart); SwapBuffers(GetDC(window_handle));  
    • By Tchom
      Hey devs!
       
      I've been working on a OpenGL ES 2.0 android engine and I have begun implementing some simple (point) lighting. I had something fairly simple working, so I tried to get fancy and added color-tinting light. And it works great... with only one or two lights. Any more than that, the application drops about 15 frames per light added (my ideal is at least 4 or 5). I know implementing lighting is expensive, I just didn't think it was that expensive. I'm fairly new to the world of OpenGL and GLSL, so there is a good chance I've written some crappy shader code. If anyone had any feedback or tips on how I can optimize this code, please let me know.
       
      Vertex Shader
      uniform mat4 u_MVPMatrix; uniform mat4 u_MVMatrix; attribute vec4 a_Position; attribute vec3 a_Normal; attribute vec2 a_TexCoordinate; varying vec3 v_Position; varying vec3 v_Normal; varying vec2 v_TexCoordinate; void main() { v_Position = vec3(u_MVMatrix * a_Position); v_TexCoordinate = a_TexCoordinate; v_Normal = vec3(u_MVMatrix * vec4(a_Normal, 0.0)); gl_Position = u_MVPMatrix * a_Position; } Fragment Shader
      precision mediump float; uniform vec4 u_LightPos["+numLights+"]; uniform vec4 u_LightColours["+numLights+"]; uniform float u_LightPower["+numLights+"]; uniform sampler2D u_Texture; varying vec3 v_Position; varying vec3 v_Normal; varying vec2 v_TexCoordinate; void main() { gl_FragColor = (texture2D(u_Texture, v_TexCoordinate)); float diffuse = 0.0; vec4 colourSum = vec4(1.0); for (int i = 0; i < "+numLights+"; i++) { vec3 toPointLight = vec3(u_LightPos[i]); float distance = length(toPointLight - v_Position); vec3 lightVector = normalize(toPointLight - v_Position); float diffuseDiff = 0.0; // The diffuse difference contributed from current light diffuseDiff = max(dot(v_Normal, lightVector), 0.0); diffuseDiff = diffuseDiff * (1.0 / (1.0 + ((1.0-u_LightPower[i])* distance * distance))); //Determine attenuatio diffuse += diffuseDiff; gl_FragColor.rgb *= vec3(1.0) / ((vec3(1.0) + ((vec3(1.0) - vec3(u_LightColours[i]))*diffuseDiff))); //The expensive part } diffuse += 0.1; //Add ambient light gl_FragColor.rgb *= diffuse; } Am I making any rookie mistakes? Or am I just being unrealistic about what I can do? Thanks in advance
    • By yahiko00
      Hi,
      Not sure to post at the right place, if not, please forgive me...
      For a game project I am working on, I would like to implement a 2D starfield as a background.
      I do not want to deal with static tiles, since I plan to slowly animate the starfield. So, I am trying to figure out how to generate a random starfield for the entire map.
      I feel that using a uniform distribution for the stars will not do the trick. Instead I would like something similar to the screenshot below, taken from the game Star Wars: Empire At War (all credits to Lucasfilm, Disney, and so on...).

      Is there someone who could have an idea of a distribution which could result in such a starfield?
      Any insight would be appreciated
    • By afraidofdark
      I have just noticed that, in quake 3 and half - life, dynamic models are effected from light map. For example in dark areas, gun that player holds seems darker. How did they achieve this effect ? I can use image based lighting techniques however (Like placing an environment probe and using it for reflections and ambient lighting), this tech wasn't used in games back then, so there must be a simpler method to do this.
      Here is a link that shows how modern engines does it. Indirect Lighting Cache It would be nice if you know a paper that explains this technique. Can I apply this to quake 3' s light map generator and bsp format ?
  • Popular Now